The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of integrated circuit evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased.
Some semiconductor fabrication processes require filling a trench or opening with a conductive material, such as a metallic material. However, as the geometry size of the ICs continue to decrease, it is increasingly more difficult to fill the trench or opening with the conductive material without voids or gaps.
Therefore, while existing methods of filling trenches with a conductive material have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.